Did some work on the car (intake plenum had shifted, causing unmetered air to enter the intake after the MAF) and must have bumped something as now the car idles at 2,000 revs immediately after start. Applying throttle only brings the revs up and maintains that throttle position.

Checked throttle cable and gas pedal for play, nothing different from previous there. Went under the car and checked for cable play at the throttle body, nada. Unplugged the IACV on the throttle body, no change. Tried pulling the battery for 10 minutes to see if that helped, also no.

My next thought is the TPS needs to be reset.

And I’m hoping someone in the Dallas-area might have a working VCM 1 I can borrow so I can reset the TPS as my eBay unit is not communicating with the car.

Any other suggestions would be welcome!

 

I have 2 WDS and 2 IDS units working at this time (AHOLBRO1 is using my third WDS unit for the time being).

You can drive over to Decatur area in Wise County. I live just North of Boyd TX off FM (Farm to Market Road) 730.

You can send me a Private Message if you want to set the TPS and perform an Oxygen Orientation Setup.

bob

 

As a last resort. With the engine warm and running, see if unplugging, then replugging in the TPS sensor, on the underside of the throttle body helps.

I'd prefer it with the car running to see if there's any difference as the wires are pulled/pushed around. The harness on my car gets a little finicky if I move it around much. The harness is due to be replaced.

 

The XJR TPS is incredibly difficult to access!!!

bob

 

Ahh yes, I forgot about the supercharger....

 

I bought a new IACV just in case that is the problem. The valve arrived so I got the car in the shop yesterday.
Throttle is not closing all the way so the spring/spindle needs to come off for diagnosis.

Car is hanging on the lift so more info when I get it. (I work slow in semi-retirement)

bob

 

Does the car have the modified return spring arrangement fitted?
As I understand it there was an additional spring which was fitted by dealers at the time when problems arose. My car has it, so I have the spring which wraps around the throttle spindle, and a separate spring attached via a plastic arm which pulls the mechanism directly shut.

 

I drove a '95 XJR for years.

FWIW.....

Eventually 'something' happened where the throttle would not release fully. I'd have to slacken the throttle cables to let the idle drop and then readjust them. All would be well for a few weeks or months...but the high idle always came back and I'd have to repeat the process.

The cables themselves seemed OK. That is, the action seemed smooth and there were no kinks. I concluded....but never actually confirmed in any way....that the Traction Control unit was somehow sticking.

Cheers
DD

 

The throttle does have a 'helper-spring'. The springs are not the problem. There was some debris in the intake that jammed the throttle plate from closing completely.

Throttle pot adaptation performed again and the engine idles at 800.

bob

 

Doug raises an interesting point about the traction control. There is a potentiometer on top of it too, and I wondered the same thing.
BTW, should it not idle at 650rpm? Mine always has, and I am delighted to say it is finally doing it again.

 

I did not check the idle at engine operating temp. I just was glad it was 800 when I started it COLD.

I them performed the throttle pot adaptation.

bob

 

Yes, make sure you remove your work towels from the intake before buttoning everything back together!

Looking forward to getting behind the wheel again tomorrow!